Cab signaling system fob railway yards



Aug. 28, 1928.

1,681,977 0. w. FAILOR CAB SIGNALING SYSTEM FOR RAILWAY YARDS Original Filed Feb. 24, 1927 2 Sheets-Sheet 1 v INVENTOR:

6.14. Fqf/a}, 9 f U .Q-Z-W asst ma non 7 Patented Aug. 28, 1928.

,UNITED, STATES I 1,681,977 PATENTOFFICE;

CHARLES W. FAILOR, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SVVISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

CAB SIGNALING SYSTEM FOR RAILWAY YARDS.

Application filed February 24, 1927, Serial No. 170,495. Renewed July 9, 1928. Y

My invention relates to cab signaling systems for railway yards, and has for an object the provision of means controlled trom a central point for transmitting indications o to a shifting locomotive. My invention 1s particularly well adapted to, though by no means limited to, cab signaling for freight distributing yards.

c I will describe one form of signaling sys- Ill tem embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1

and 1 when placed side by side in the or 5 der named, constitute a diagrammatic view showing one form of signaling system embodying my invention.

Referring to the drawing, the reference character Y designates a distributing yard which as here shown comprises siX parallel tracks. Ti'afiic normally enters the yard Y from a main track T, and is distributed onto the yard tracks by a ladder track T Traffic leaves the yard Y on a ladder track T and passes over a scale U, which is usually located on a hump, and from which it moves into a classification yard, not shown in the drawing. In accordance with usual practice, cars are collected on the several tracks of the yard Y, and are then pushed over the hump by a shifting locomotive. The purpose of the present invention is to enable an operator in a control cabin to transmi't signal indications to the shifting locomotive on any one of the tracks constituting the yard Y.

Each track is provided with a track selecting relay designated by the reference character It with an exponent corresponding to the number given to the track. The indication transmitted to the locomotive is selected by indication selecting relays, each designated by the letter F with a distinguishing exponent. All of the relays R and F are normally open, and all of these'relays are controlled from an operating panel A located in the control cabin. This operating panel A is provided with a plurality of track selecting push buttons each designated by the reference character C with an exponent corresponding to the number of the track which it selects. The operating panel also contains a plurality of indication selectpa tbuttons l5, one corresponding it each of'the indication selecting relays F. Each push button comprises a normally closed contact 9 and a normally open contact 10. lVhen the push button is operated the contact 9 is opened and contact 10 is closed, whereas when the push button is released it automatically returns to its normal condition. y

Power for the operation of the relays is obtained from the secondary of a transformer J, the primary of which is connected with a source of alternating current not shown in the drawing. I will assume that all of the relays are open, and that the operatordesires to close track selecting relay R To do this he closes a snap switch 5 and operates push. button C Current then flows from the upper terminal of the secondary of transformer J, through wire D, switch 5. normally closed contact 9 of each push button C C, C", G and C normallyopen contact 10 of push button C wire 11, winding of relay R wire 12, back contact 13 of relay R back contact 14 of relay R back con tact 15 of relay Rf, back contact 16 of relay R oack contact 17 of relay R, and wire X to the lower terminal of the secondary of transformer J. After relay R becomes closed, the operator releases push but-ton C whereupon relay R remains closed due to a stick circuit which passes from wire D, through switch .5, contact 9 on each push button C, wires 18 and 19, winding of relay R front contact 20 of relay R wire 12 and contacts 13, 14, 15, 16 and 17 as before, to wire X. Relay R will then remain closed until any one of the push buttons C is operated, whereupon the stick circuit for relay R will then be opened at contact 90f such push button. Furthermore, should any one of the relays R R R, R or R become closed, thestick circuit for relay R will be opened at the back contact 13, 14,15. 16 or 17 of such relay and relay R will release.

The pick-up circuit for relay R passes from wire D, through the switch 5, contact 9 of each push button C C C and C contact 10 of push button C wire 21, winding of relay R back contact 22 of relay R back contact 14 of relay R back contact 15 of relay R back contact 16 of relay R and back con; t 1? of relay R to'wire Th. stick circuit to el-a}; R" mews Hem fire D,

through normally closed contact 9 of each of the push buttons C, wire 18, front contact 23 of relay R winding of relay R and thence through contacts 22, let, 15, 16 and 17 as be foref-to when." if i "Ilie'pick' up circuit for relay R" is from wire D, through normally closed contact 9 of each push button C, Q, and, C, contact 10 of push button G wire 24, winding of relay R back con act 25 01; 1 .35, sack contact 26 of relay b ack contact 15 of relay R", back contnc t 1601' relay B5", and back contact 17 of relaylRf to wire X. The stick circuit forrelay Rfis from wire D, through normally close d contact9 of each push button C, wire 18, wire 27;, front contact 28 of relay R windingiof relay back contact 250i relay R contact of relay R back contact 15 of relay R, back contact 16 of relay R, -99 i on t &7 Of. layR to wire- A lhe p e iJpcr uit. ifor relay P includes thefnurmalyclosed; contact 9 of each push button Cl-flandC contact 10 of push button C, wire 29, winding of relayll, and back cqntacts t), 31, l fi an d 17 of relays R, R l and lifi. The stick circuit for relay includes the normally-closed contact 9 of each lpush but tonC, front contact 35 of relay Rf, andbaclc'contactsflfl, 31, 3:2, 16and 17 of re a in -In y R, The piclr-up circuit for relay Rf includes normally.closedfcontact 9. o l. push button (l contactjluoi push button C, wire 36, windinq of relay R and the, back contacts 37,38,59, 40 and, 17 0f the remaining nelays R The sticl r eireuit for relay B includes the lloljmallyclosed contact 9 oteach push l'nittonlfC front contact 43 of relay R the winclingof relay RP, and back contacts 37, 38, 39, 40 and 17,;01 thercmaininq relays R. The pick-{up circuit; forrelay includes the nor nially open contact 10 of. push button C the windin" of relayR, and back contacts l5, 4C6, 4L7, 418 andfi l) of relays R to R inclusive. The. stick. circuit for relay R includesthe normally closed contact 9 of each pushbutton ,C, contact 34 of relay R, the winding of relay R), and back contacts 45, 46, 47, i S and 4979f relays to R; incli wiretwillbe seen from the foregoing that the operator cannpt' close any relay R unless all of theremain ngirelays R are open, and it will also heseen that any relay R which is closed will be opened by the operation of any pusli button G and also by the closure of any.

. Wetla R- fwill new ass m iha t p or esires to cose the indication selecting relay. F To do this he, operatesuthe push button E whereupon current. flows from wire D, through switch 5, wire 50, normally closedcontact9 ofieachpush button E E ancLE contact. 10 0f pushbutton EB, wire 51, winding of relayli back contact 52- of. relayF and back contact 53 of relay F to wire X. \V hen push button E" is released, a stick circuit for relay F is closed, which circuit is from wire 1), through switch 5, wire normally closed contact 9 Oiieach push button E, wfre54l, front contact ofijelay F winding of relay F and back contacts" 52 and 53 to wire X.

The pick-up circuit for relay F includes the normally closed contact 91 of each push button E and E contact 10 of push button E wire 56, winding of relay F back contact 57 of relay F back contact 530i relay F and wire X. The stick circuit for relay F includes contact 9 of each push button E,

front contact 58 of relay F the winding of relay F and back contacts 57 and 53 of relay F and F respectively.

The pick-up c rcuit for. relay F includes contact 9 of push button E contact lO'of push button E wire 59, winding of relay F back contact 60 01? relay/F and backcontact 61 of relay F The stick circuit for relay F includes the normallyclosedcontact 9 of each push button E, front contact 62 of relay F t windingiof relay F and! back contacts 60 an d 61 of relays. and E respectively.

It will be seen from. the foregoing that the operator-cum j close any one. DIE-tilt indica tion selecting relays F unless both of the remaining relays I? are open, andthat after one otthcse relays F is closed, .it will become opened it any one oi. the push. buttons E is operated and also if either ofthe remaining relays F becomes closed.

-Each push button in the operating panel A is'flprovidedjwith an indicator lamp designated by thereterence character L with the same exponent as that applied to the corresponding push button. The lamps L are supplied. with current from the secondary 41 of a transformer K, the primary 3 of which connected with the secondary oi transformer .J The circuit/for lamp L is from secondaryl oii transformer K, through wireDK lainpl l, front contact 63 of relay It, and wire X to the secondary lof trans formerli hen relay R closes in response to. operation ot. push button C lamp L and the circuit for lampL includes contact 71' of. relayFB. The circuitfor lamp I), which is associated with push button E is iromwire D1, through lamp L back contact 99 otrelay Fl, hack cmugact 9i. oi. rel ay Tum lie

ill

-' 78, 76 and 72.

' thereby closing re 'F and back contact 82 of relay F to wire X This lamp will therefore be closed when and only when all three of the indication selecting relays are open.

Each track of the yard Y is provided with a trackway circuit for inductively transmitting indication to a vehicle on the track. As here shown, this trackway circuit in cludes one of the track rails 91 and an auxiliary conductor 90 parallel with and close to the other track rail. The track rail 91 is isolated from the ladder tracks T and T by insulated joints 2. This trackway circuit is intended for co-operation with vehicle-carried apparatus responsive to alternating current flowing in opposite directions at a given instant in the rail 91 and the auxiliary conductor 90. It will be observed that the trackway circuit is not shunted by the wheels and axles of a vehicle, so that the indications will be transmitted to a vehicle provided with receiving apparatus, whether the receiving apparatus is at one end or the other of the vehicle, and whether the vehicle is preceded or followed by other vehicles on the same track.

In the form here shown, the indications are produced by supplying to the trackway circuits alternating current periodically interrupted at different frequencies, and this periodic interruption is accomplished by a coding device G. The device G comprises a motorr7 operating a plurality of cams 8, which in turn actuate a plurality of contacts The cam 8 has only one swell, so that contact 78 is closed only once for each complete revolution of this cam. Cam 8 has two swells, so that contact 76 operated by this cam is closed twice forcach revolution of the cams. Cam 8 has three swells, so that contact 72 is closed three times for each revolution of the cam. Contact 78 produces what I will term the back up signal. Contact 76 produces what I will term the proceed at reduced speed indication. Contact 72 produces what I will term proceed at regular speed indication.

hen the switch 5 is closed. the motor 7 of the coding device G is supplied with current by a circuit which passes from wire I), through switch 5, wire 6, and windings of motor 7 to wire X. It follows that when the switch 5 is closed, the codingrdevice G is con-- tinuously operated.

I will now assume that all parts of the apparatus are in the positions illustrated in the drawing, and that the operator desires to transmit a proceed at regular speed indication to a locomotive on track 1. He first closes switch 5, thus setting motor 7 of coding device G in operation and also supplying current to any circuit which may subsequently be closed at the various push but tons. He then 0 erates push button C I ay R As soon as this relay closes, lamp L becomes lighted, whereupon the operator releases push button C and operates push button E This closes indica tion relay F and as soon as the latter relay closes, lamp L becomes lighted, whereupon the operator releases push button E Alternating current is then supplied to the primary 101 of an indication transformer H,

through contacts 7 2 of the coding device. G, the circuit being as follows: From wire D, through switch 5, wire 6, contact 72 of coding device Gr, contact 73 of relay F P wire 74;, primary 101 of transformer H, and wire 7 5 to wire- X. The secondary 100 of transformer H is then connected with the trackway circuit for track 1, the circuit being from secondary 100, through back contact 83 .of relay R, back contact 84 of relay R backcontact 85 of relay It, back contact 86 of relay R back contact 87 of relay R front contact 88 of relay R wire 89, auxiliary conductor 90 for track 1, track rail 91 of track 1, wire 92, front contact 94 of relay R back contacts 95, 96, 97, 98 and 99 of relays R R', R, R and R, respectively, to secondary 100 of transformer I-I. Alternating current periodically interrupted at the frequency corresponding to the'proceed at regular speed indication is thus transferred to the traclzway circuit for track 1.

If the operator desires to transmit the proceed at reduced speed indication to a locomotive on track 1, the procedure is the same as before, except that he operates push button E instead of push button E The circuit for the primary 101 of transformer I-I then includes contact 76 of the coding device G and contact 77 of relay F If the operator desires to transmit a back up indication to a locomotive on track '1, he operates push button E thereby closing relay F The circuit for primary 101 of trans former H is then the same as before, except that it includes contact 78 operated by the coding device G and contact 79 of relay F I will now assume that the operator desires to transmit an indication to a locomotive on track 2. To do this, he operates push button C thereby closing track selecting relay R The indication which will be transmitted will, of course, depend on the indication selecting relay F which is closed, and the circuit for the secondary 100 of transformer II will pass through contacts 83, 84,, 85 and 86, front contact 102 of relay R wire 1041, auxiliary conductor 90 of track 2. track rail 91 of track 2, wire 105, contact 103 of relay R and contacts 96, 97, 98 and 99 to secondary 100. Similarly, if the operator desires to transmit an indication to track 3,'track 4, track 5 or track 6, he closes track selecting relay R R, R or R. IVhen relay R isclosed, the circuit for secondary 100 of transformer H'passes through contacts 841. and 85, front contact 106 of relay R ill wire 108, conductor 90 and track rail-9-1 of track 3, wire 109, contact 107 of relay R and contacts 97, 98 and 99 to the secondary 100. lVhen relay It is closed, the trackway cir-I cuit includes contacts 83 and Sl, contact 110, of relay R wii'c 112, conductor 90 and rail 91 oi track 4, wire 113, contact 111 of relay R and contacts 98 and 99.' lVhen relay R" is closed, the circuit for secondary 100 includes contacts?) oi relay R, contact 11% of relay Bf, wire 11-6, conductor 90 and rail 91; ott'rack 5, wire 117,, contact 115 of relay R and, contact 9910f relay R. When relay R is closed, the circuit for secondary 100 includes contact 120 of relayR, wire 118, conductor 90 and wire91 of track 6, wire 11%),and contact 121 ofrelay R. f

It will be noted that contact 9. of push button E is included inthe stick circuit for each indication selecting relay F. It the operator desires to transmit a. stop indication toa vehicle on any track after having transmitted one of the other indications, he operates push button E thereby opening whichever indication selecting relay F had been closed, and so discontinuing the indication, which had previously been given. As soon as this stop indication becomes effective, lampL is lighted because all three of the indication relays F are open. The operator may then transmit any other inclication to such vehicle by operating .any other of the push buttons E, and this procedure may be continued untilthe vehicle has made all the movements desired by the operator. Alter such movements are completed, the operator opens switch 5, thereby opening whichever relays R and F may be closed, and stopping the motor 7 of coding device G.

Although I have herein shown and de scribed only one form of apparatus enibodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope o'l my invention.

Having thus described my invention what I claim is: r

1. A cab signal system for .a railway receiving yard, compi'isong a trackway circuit foreaeli tracktor inductivelytransmitting indications to a vehicle on the track, manual.-

lycontrolled means for selecting any one of said circuits for operation, and other manually controlledmeans forsupplying to such ceiving yard, comprising a trackwa-y circuit for eachtrack for inductively transmitting indications to a vehicle on the track, manu ally controlled means for selecting any one otsaid circuits for operation, and other manually controlled means for supplying to'such selected circuit alternating current periodi cally interrupted at any one of a plurality of diiierent frequencies. V

3. A cab signal system for a railway receiving yard, comprising a trackway circuit for each track for inductively transmit-ting indications to a vehicle on thetrack, a trans former, manually: controlled means for sup.- plying the primary ozt said. transformer with alternating current periodically interrupted at any desired: one of a plurality of different frequencies, and other manually controlled: means for connecting the secondary of said transformer with any desired one of said traclrway circuits.

4'. A cab signal system for a railway receiving yard, comprising a trackway circuit for each track for inductively transmitting indications to avehicle on the track, a trans former, manually controlled means for supplying the primary of said transformer with alternating current having any desired one of a plurality of ditlerent characteristics, and other manually controlled means for connecting thesecondaryo'f said transformer. with any desired one of said trackway circuits.

5. A cab signal: system fora railway receivinq yard, comprising a trackway circuit for each track forinductively transmitting indications to a vehicle on thetrack, a plurality of normally open indication selecting relays, a plurality of normally open track selecting relays one for eaclrtrackwaycircuit, manually controlled-'ineans for. closing any desired oneot said indication selecting relays and any desired one of said track selecting relays, and means controlled by said relays "for impressing a distinctive current determined I by vthe indication selecting relay which is closed on the trackway circuit corresponding to the track selecting relay which is closed; 7 l

6. A cab signal system for a railway re-v ceiving yard, comprising a trackway circuit for each track for inductively transmitting indications to a'vehicle onthe track,'a plurality of'normally open-indication selecting relays, a plurality of normally open traclrselectingrelays one for each trackway circuit, maniuilly controlledmeans for closingiany desired one of said indication selecting relays and any desired one of said track selecting relays, a source of alternating cur-rent, means- Jul) for periodically interrupting the current from said source at any one of a plurality ofdifferent -frequencies depending on the indication selecting relay which is closed, and means lior supplying such periodically interrupted current to anyoneof'said track way circuits depending'onfthe track selecting relay which is closed. 1

7. A cab signalsystem for a railway re ceiving yard, comprising a trackay circuit for each track'for inductively transmitting indications to-a vehicleonthetraclga plu rality of normally open, indication. s lecting relays, a pluralit'y of normally open track selecting relays one for each trackway circuit, manually controlled means for closing any desired one of said indication selecting relays and any desired one of said track selecting relays, a transformer, means for supplying the primary of said transformer with alternating current periodically -inter rupted at any one of a plurality of different frequencies depending upon which of said indication selecting relays is closed, and means for connecting the secondary of said transformer with any one of said trackway circuits depending upon which of said track selecting relays is closed.

8. A cab signal'system for a railway re ceiving yard, comprising a trackway circuit for each track for inductively transmitting indications to vehicles on the track, a plurality of normally open indication selecting relays, a plurality of normally open track selecting relays one for each trackway circuit, a plurality of indication selecting push buttons one for each indication selecting rer: lay, a plurality of track selecting push but tons one for each track selecting relay; each push button having a normally closed contact and a normally open contact, a pick-up circuit for each indication selecting relay including a back contact of each of the re maining indication selecting relays and the normally open contact of the associated indication selecting push button, a stick circuit for each indication selecting relay in- .4 eluding a front contact of such relay and a back contact of each of the remaining indication selecting relays as well as the normally closed contact of each indication selecting push button, a pick-up'circuitfor each track selecting relay including aback contact of each of theremaining track selecting relay and the normally open contact of the associated track selecting push button, a stick circuit for each track selecting relay including a front contact of such relay and a back contact of each of the remaining track selecting relays as well as the normally closed contact of each track selecting push button, and means controlled by said relays for impressing adistinctive current'determined by the indication selecting relay which is closed on the trackway circuit corresponding to the track selecting relay which is closed. 9. A cab signal system for a railway receiving yard, comprising a trackway circuit for each track for inductively transmitting indications to vehicles on the track, a plurality of normally open indication selecting relays, a plurality of normally open track selecting relays one for each trackway circuit, a plurality of indication selecting push buttons one for each indication. selecting relay, a plurality of track selecting push buttons one for each track selecting relay, each push button having a normally closed contact and a normally open contact, a pick-up circuit for each indication selecting relay including a back contact of each of the remaining indication selecting relays and the normally open contact of the associated indication selecting push button, a stick circuit for each indication sclecting relay including a front contact of such relay and a back contact of each of the remaining indication selecting relays as well as the normally closed contact of each indication selecting push button, a pickup circuit for each track selecting relay including a back contact of each of the remaining track selecting relay and the normally open contact of the associated track selecting push button, a stick circuit for each track selecting relay including a front contact of such relay and a back contact of each of the remaining track selecting relays as well as the normally closed contact of each track selecting push button, a trans former, means for supplying the primary of said transformer with alternating current periodically interrupted at any one of a plurality of different frequencies depending upon which of said indication selecting relays is closed, and means for connecting the secondary of said transformer with any one of said trackway circuits depending upon which I of said track selecting relaysis closed. a

10. A cab signal system for a railway receiving yard, comprising a trackway circuit for each track for inductively transmitting indications to vehicles on the track, a plurality of normally open indication selecting relays, a plurality of normally open track selecting relays one for each trackway circuit, a plurality of indication selecting push buttons one for each indication selecting relay, a plurality of track selecting push buttons one vfor each track selecting relay,imeans for closing each indication'selecting relay when the associated push button'is operated and for subsequently keeping such relay energized after the push button is released until another indication selecting relay is closed or another indication selecting push button 1 is operated, means for closing each track select-ing'relay when the associated push button is operated and for'subsequently keeping such track selectingrelay closed until another track selecting relay becomes closed or another track selecting push button is operated, and means controlled by said relays for impressing a distinctive current determined by the indication selecting relay which is closed on the trackway circuit corresponding to the track selecting relay which is closed. I

11. A cab signal system for a railway receiving yard, comprising a trackway circuit for each track for transmitting indications to vehicles on the track, a plurality of normally open indication selecting relays, a plurality of normally open track selecting relays one for each trackway circuit, a plurality of indication selecting push buttons one for each indication selecting relay a plurality of tracksclecting push buttons one for each track selecting relay, means for closing each indication selecting relay when the associated push button is operated and for subsequently keeping such relay energized after the push button is released until another indication selecting relay is closed or another indication selecting push button is operated, means for closing each track selecting relay when the associated push button is operated and for subsequently keeping such track selecting relay closed until another track selectlng relay becomes closed or another track selecting push button is operated, a transformer, means for supplying the primary of said transformer with alternating; current perlodlca-lly' interrupted at any one of a plurality of diii'erent frequencies depending upon which of said indication selecting relays is closed, and means for connecting the secondary of said trans former with any one of said traclrway circuits depending upon which of said track selecting relays is closed. g

12. A signal system for a railway yard, comprising a plurality of normally, open indication selecting relays, a plurality of normally open track selectm relays one for each tra clg'a plurality of lndication selecting push buttons one for each indication selectingrelay, a plurality of track selecting push buttons one for each track selecting relay, means for closing each indication selecting relay when the associated push button is operated and for subsequently keeping such relay energized after the push button is released until another indication se- 'lectrng relay is closed or another indication selecting push button is operated, means for closing each track selecting relay when the associated ush button is operated and for subsequent y keeping such. track selecting relayclosed' until another track sele'cting relay becomesclosed or another track selecting push button is operated, and means con trolled bysaid relays for transmittingadistinctive signal determined by the indication selecting relay which is closed to the track corresponding to the track selecting relay which is closed. a

13. A signal system for a railway yard, comprising plurality of normally open in" dication selecting relays, a plurality of normally open track selecting relays one for each track, a plurality of indication selecting push buttons one for each indication selecting. relay, a plurality of track selecting push buttons one for each track selecting relay, means for closing eachindication selecting relay when the associated push button is operated, means for closing each track selecting relay when the associated push butpush buttons one for each indication se- .lecting relay, a plurality of track selector push buttons one for each traekselectlng track selecting relays one for eachtrackway circuit, a plurality of ind cation selectmg relay, means for closing each indication selecting relay when the associated, push button is operated and for subsequently keeping such relay energized after the push button is released until another indication selecting relay is closed or another indication lecting relays, aplurality of normally open selecting push button is operated, means for closing each track selecting relay when the associated push button is operatedfland for subsequently keeping such track selecting relay closed until another trackselecting relay becomes closed or another track-selecting push button is operated, a transformer, means for supplying the primary of said transformer with alternating current 'peri odically interrupted at any one of a plurality of different frequencies'dependingupon which of said indication selecting, relays is closed, and means for connecting, the sec ondary of said transformer with any one of said trackway circuits depending upon which of saidtrack selecting relays is closed,

15. A cab signal system for a railway.

yard, comprising a trackway circuit for each track for signaling inductively to a vehicle on the track, and manually operable means for supplying signaling current to any selected one of said circuits and for than one circuit at a time. a

16. A cab signal system for a railway yard, comprising a 'trackwaycircuit for each track for signaling inductively to a preventing the supply of current to more vehicle on the track, atransformer thepri-q' mary of which isconstantly supplied with alternating current, and manuallyroperable means for connecting these'condary of said transformer with any selected: one of said circuits and for preventing said'secondary from being connected with more than one circuit at a time. i

17. A cab signal system for a railway yard, comprising a traekway circnitfor' each track for signaling inductively to a vehicle on thetrack, and manually operable means for supplying signaling eurrent to any selected one of said circuits. 7

18. A cab signaling system for a railway yard having a plurality of tracks, comprising a manually controlled circuit controller for each track having a normally closed contact and a normally open contact, all of said normally closed contacts being connected in series with a source of current, and an individual trackway circuit for each track connected with the normally open contact of the associated circuit controller, whereby current may be supplied to any selected circuit but cannot be supplied to more than one circuit at a time.

19. A cab signaling system for a railway yard having a plurality of tracks, comprising a series of manually controlled circuit controllers one for each track and each having a movable member coacting with a normally closed fixed contact and a normally open fixed contact, a source of current connected with the movable member of the first circuit controller, a connection between the normally closed contact of each circuit controller and the movable member of the next circuit controller, and an individual trackway circuit for each track connected with the normally open contact of the associated circuit controller whereby current may be supplied to any selected circuit but cannot be supplied to more than one circuit at a time.

20. A cab signaling system for a railway yard having a plurality of tracks, comprising a series of manually controlled circuit controllers one for each track, each controller having two movable members and each movable member coacting with a normally closed fixed contact and a normally open fixed contact, a source of current having its terminals connected with the two movable members of the first circuit controller, mean for connecting the two normally closed contacts of each controller with the two movable members respectively of the next controller, and an individual trackway circuit for each track for signaling inductively to a vehicle on the track and hav ing its terminals connected with the two normally open contacts respectively of the associated circuit controller, whereby said source may be connected with any selected one oi. said trackway circuits but cannot be connected with more than one circuit at a time.

In testimony whereof I afiix my signature.

CHARLES W. FAILOR. 

